Producing Change to Understand the Social Determinants of Health: The Promise of Experiments for Social Epidemiology.

In this commentary, invited for the 100th anniversary of the Journal, we discuss the addition of randomized experiments, along with natural experiments that emulate randomized trials using observational data, as designs in the social epidemiologist's toolbox. These approaches transform the way we define and ask questions about social exposures. They compel us to ask questions about how well-defined interventions change a social exposure that might lead to changes in health. As such, experiments are of unique public health and policy significance. We argue that they are a powerful approach to advance our understanding of how well-defined changes in social exposures impact health, and how credible social policy reforms may be instrumental to address health inequalities. We focus on two research designs. The first is a "pure" randomized controlled trial (RCT) in which the investigator defines and randomly assigns the intervention. The second is a natural experiment, which exploits the fact that policies or interventions in the real world often involve an element of random assignment, emulating an RCT. To give the reader our bottom line: While acknowledging their limits, we continue to be very excited about the promise of RCTs and natural experiments to advance social epidemiology.

Employee Cardiometabolic Risk Following a Cluster-Randomized Workplace Intervention From the Work, Family and Health Network, 2009-2013.

Objectives. To examine whether workplace interventions to increase workplace flexibility and supervisor support and decrease work-family conflict can reduce cardiometabolic risk. Methods. We randomly assigned employees from information technology (n = 555) and long-term care (n = 973) industries in the United States to the Work, Family and Health Network intervention or usual practice (we collected the data 2009-2013). We calculated a validated cardiometabolic risk score (CRS) based on resting blood pressure, HbA1c (glycated hemoglobin), HDL (high-density lipoprotein) and total cholesterol, height and weight (body mass index), and tobacco consumption. We compared changes in baseline CRS to 12-month follow-up. Results. There was no significant main effect on CRS associated with the intervention in either industry. However, significant interaction effects revealed that the intervention improved CRS at the 12-month follow-up among intervention participants in both industries with a higher baseline CRS. Age also moderated intervention effects: older employees had significantly larger reductions in CRS at 12 months than did younger employees. Conclusions. The intervention benefited employee health by reducing CRS equivalent to 5 to 10 years of age-related changes for those with a higher baseline CRS and for older employees. Trial Registration. ClinicalTrials.gov Identifier: NCT02050204. (Am J Public Health. 2023;113(12):1322-1331. https://doi.org/10.2105/AJPH.2023.307413).

Effects of Pension Eligibility Expansion on Men's Cognitive Function: Findings from Rural South Africa.

Two-thirds of people living with Alzheimer's disease and related dementias (ADRD) live in low- and middle-income countries, and this figure is expected to rise as these populations are rapidly aging. Since evidence demonstrates links between socioeconomic status and slower rates of cognitive decline, protecting older adults' cognitive function in resource-limited countries that lack the infrastructure to cope with ADRD is crucial to reduce the burden it places on these populations and their health systems. While cash transfers are a promising intervention to promote healthy cognitive aging, factors such as household wealth and level of education often confound the ability to make causal inferences on the impact of cash transfers and cognitive function. This study uses a quasi-experimental design, leveraging an exogenous expansion to the Old Age Pension for men in South Africa, to approximate causal associations with cognitive function. We found evidence that there is a potential benefit of cash transfers at an earlier age for older individuals. As such, transfers such as pensions or other forms of direct basic income transfers may hold promise as potential interventions to promote healthy cognitive aging.

Eight-Year Depressive Symptom Trajectories and Incident Stroke: A 10-Year Follow-Up of the HRS (Health and Retirement Study).

BACKGROUND: Evidence suggests a link between depressive symptoms and risk of subsequent stroke. However, most studies assess depressive symptoms at only one timepoint, with few examining this relationship using repeatedly measured depressive symptoms. This study aimed to examine the relationship between depressive symptom trajectories and risk of incident stroke. METHODS: This prospective cohort included 12 520 US individuals aged ≥50 years enrolled in the Health and Retirement Study, free of stroke at study baseline (1998). We used the 8-item Center for Epidemiologic Studies Depression scale to assess depressive symptoms (high defined as ≥3 symptoms; low <3 symptoms) at 4 consecutive, biennial timepoints from 1998 to 2004. We assigned individuals to 5 predefined trajectories based on their scores at each timepoint (consistently low, decreasing, fluctuating, increasing, and consistently high). Using self-reported doctors' diagnoses, we assessed incident stroke over a subsequent 10-year period from 2006 to 2016. Cox regression models estimated the association of depressive symptom trajectories with risk of incident stroke, adjusting for demographics, health behaviors, and health conditions. RESULTS: During follow-up, 1434 incident strokes occurred. Compared with individuals with consistently low symptoms, individuals with consistently high depressive symptoms (adjusted hazard ratio, 1.18 [95% CI, 1.02-1.36]), increasing symptoms (adjusted hazard ratio, 1.31 [95% CI, 1.10-1.57]), and fluctuating symptoms (adjusted hazard ratio, 1.21 [95% CI, 1.01-1.46]) all had higher hazards of stroke onset. Individuals in the decreasing symptom trajectory group did not show increased stroke risk. CONCLUSIONS: Depressive symptom trajectories characterized by high symptoms at multiple timepoints were associated with increased stroke risk. However, a trajectory with depressive symptoms that started high but decreased over time was not associated with higher stroke risk. Given the remitting-relapsing nature of depressive symptoms, it is important to understand the relationship between depressive symptoms and stroke risk over time through repeated assessments.

Health Selection Into Eviction: Adverse Birth Outcomes and Children's Risk of Eviction Through Age 5 Years.

Adverse birth outcomes put children at increased risk of poor future health. They also put families under sudden socioeconomic and psychological strain, which has poorly understood consequences. We tested whether infants experiencing an adverse birth outcome-low birthweight or prematurity, as well as lengthy hospital stays-were more likely to be evicted in early childhood, through age 5 years. We analyzed 5,655 observations contributed by 2,115 participants in the Fragile Families and Child Wellbeing Study-a national, randomly sampled cohort of infants born in large US cities between 1998 and 2000-living in rental housing at baseline. We fitted proportional hazards models using piecewise logistic regression, controlling for an array of confounders and applying inverse probability of selection weights. Having been born low birthweight or preterm was associated with a 1.74-fold increase in children's hazard of eviction (95% confidence interval: 1.02, 2.95), and lengthy neonatal hospital stays were independently associated with a relative hazard of 2.50 (95% confidence interval: 1.15, 5.44) compared with uncomplicated births. Given recent findings that unstable housing during pregnancy is associated with adverse birth outcomes, our results suggest eviction and health may be cyclical and co-constitutive. Children experiencing adverse birth outcomes are vulnerable to eviction and require additional supports.

Incidence of Cognitive Impairment during Aging in Rural South Africa: Evidence from HAALSI, 2014 to 2019.

INTRODUCTION: Despite rapid population aging, there are currently limited data on the incidence of aging-related cognitive impairment in sub-Saharan Africa. We aimed to determine the incidence of cognitive impairment and its distribution across key demographic, social, and health-related factors among older adults in rural South Africa. METHODS: Data were from in-person interviews with 3,856 adults aged ≥40 who were free from cognitive impairment at baseline in the population-representative cohort, "Health and Aging in Africa: a Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI), in Agincourt sub-district, Mpumalanga province, South Africa (2014-19). Cognitive impairment was defined as scoring <1.5 standard deviations below the mean of the baseline distribution of orientation and episodic memory scores. Incidence rates and rate ratios for cognitive impairment were estimated according to key demographic, social, and health-related factors, adjusted for age, sex/gender, and country of birth. RESULTS: The incidence of cognitive impairment was 25.7/1,000 person-years (PY; 95% confidence interval [CI]: 23.0-28.8), weighted for mortality (12%) and attrition (6%) over the 3.5-year mean follow-up (range: 1.5-4.8 years). Incidence increased with age, from 8.9/1,000 PY (95% CI: 5.2-16.8) among those aged 40-44 to 93.5/1,000 PY (95% CI: 75.9-116.3) among those aged 80+, and age-specific risks were similar by sex/gender. Incidence was strongly associated with formal education and literacy, as well as marital status, household assets, employment, and alcohol consumption but not with history of smoking, hypertension, stroke, angina, heart attack, diabetes, or prevalent HIV. CONCLUSIONS: This study presents some of the first incidence rate estimates for aging-related cognitive impairment in rural South Africa. Social disparities in incident cognitive impairment rates were apparent in patterns similar to those observed in many high-income countries.

Work Redesign for the 21st Century: Promising Strategies for Enhancing Worker Well-Being.

Work is a key social determinant of population health and well-being. Yet, efforts to improve worker well-being in the United States are often focused on changing individual health behaviors via employer wellness programs. The COVID-19 health crisis has brought into sharp relief some of the limitations of current approaches, revealing structural conditions that heighten the vulnerability of workers and their families to physical and psychosocial stressors. To address these gaps, we build on existing frameworks and work redesign research to propose a model of work redesign updated for the 21st century that identifies strategies to reshape work conditions that are a root cause of stress-related health problems. These strategies include increasing worker schedule control and voice, moderating job demands, and providing training and employer support aimed at enhancing social relations at work. We conclude that work redesign offers new and viable directions for improving worker well-being and that guidance from federal and state governments could encourage the adoption and effective implementation of such initiatives. (Am J Public Health. 2021;111(10):1787-1795. https://doi.org/10.2105/AJPH.2021.306283).

Alcohol Consumption and Sexual Risk Behavior in an Aging Population in Rural South Africa.

We sought to characterize the relationship between alcohol consumption and sexual risk-taking in an aging population in rural South Africa. A cross-sectional analysis was conducted using baseline data from the Health and Ageing in Africa: a Longitudinal Study of an INDEPTH Community (HAALSI) cohort. We elicited information on sexual risk behavior and self-reported frequency of alcohol consumption among 5059 adults ≥ 40 years old. Multivariable models showed that more frequent alcohol consumption is associated with a higher number of sexual partners (ß: 1.38, p < .001) and greater odds of having sex for money (OR: 42.58, p < .001) in older adults in South Africa. Additionally, daily drinkers were more likely to have sex without a condom (OR: 2.67, p = .01). Older adults who drank more alcohol were more likely to engage in sexual risk-taking. Behavioral interventions to reduce alcohol intake should be considered to reduce STI and HIV transmission.

Older Adults Vastly Overestimate Both HIV Acquisition Risk and HIV Prevalence in Rural South Africa.

Perceptions of HIV acquisition risk and prevalence shape sexual behavior in sub-Saharan Africa (SSA). We used data from the Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa baseline survey. Data were collected through home-based interviews of 5059 people ≥ 40 years old. We elicited information on perceived risk of HIV acquisition and HIV prevalence among adults ≥ 15 and ≥ 50 years old. We first describe these perceptions in key subgroups and then compared them to actual estimates for this cohort. We then evaluated the relationship between sociodemographic characteristics and accurate perceptions of prevalence in regression models. Finally, we explored differences in behavioral characteristics among those who overestimated risk compared to those who underestimated or accurately estimated risk. Compared to the actual HIV acquisition risk of < 1%, respondents vastly overestimated this risk: 35% (95% CI: 32-37) and 34% (95% CI: 32-36) for men and women, respectively. Respondents overestimated HIV prevalence at 53% (95% CI: 52-53) for those ≥ 15 years old and 48% (95% CI: 48-49) for those ≥ 50 years old. True values were less than half of these estimates. There were few significant associations between demographic characteristics and accuracy. Finally, high overestimators of HIV prevalence tested themselves less for HIV compared to mild overestimators and accurate reporters. More than 30 years into the HIV epidemic, older people in a community with hyperendemic HIV in SSA vastly overestimate both HIV acquisition risk and prevalence. These misperceptions may lead to fatalism and reduced motivation for prevention efforts, possibly explaining the continued high HIV incidence in this community.

Association Between Depressive Symptoms and Incident Cardiovascular Diseases.

Importance: It is uncertain whether depressive symptoms are independently associated with subsequent risk of cardiovascular diseases (CVDs). Objective: To characterize the association between depressive symptoms and CVD incidence across the spectrum of lower mood. Design, Setting, and Participants: A pooled analysis of individual-participant data from the Emerging Risk Factors Collaboration (ERFC; 162 036 participants; 21 cohorts; baseline surveys, 1960-2008; latest follow-up, March 2020) and the UK Biobank (401 219 participants; baseline surveys, 2006-2010; latest follow-up, March 2020). Eligible participants had information about self-reported depressive symptoms and no CVD history at baseline. Exposures: Depressive symptoms were recorded using validated instruments. ERFC scores were harmonized across studies to a scale representative of the Center for Epidemiological Studies Depression (CES-D) scale (range, 0-60; ≥16 indicates possible depressive disorder). The UK Biobank recorded the 2-item Patient Health Questionnaire 2 (PHQ-2; range, 0-6; ≥3 indicates possible depressive disorder). Main Outcomes and Measures: Primary outcomes were incident fatal or nonfatal coronary heart disease (CHD), stroke, and CVD (composite of the 2). Hazard ratios (HRs) per 1-SD higher log CES-D or PHQ-2 adjusted for age, sex, smoking, and diabetes were reported. Results: Among 162 036 participants from the ERFC (73%, women; mean age at baseline, 63 years [SD, 9 years]), 5078 CHD and 3932 stroke events were recorded (median follow-up, 9.5 years). Associations with CHD, stroke, and CVD were log linear. The HR per 1-SD higher depression score for CHD was 1.07 (95% CI, 1.03-1.11); stroke, 1.05 (95% CI, 1.01-1.10); and CVD, 1.06 (95% CI, 1.04-1.08). The corresponding incidence rates per 10 000 person-years of follow-up in the highest vs the lowest quintile of CES-D score (geometric mean CES-D score, 19 vs 1) were 36.3 vs 29.0 for CHD events, 28.0 vs 24.7 for stroke events, and 62.8 vs 53.5 for CVD events. Among 401 219 participants from the UK Biobank (55% were women, mean age at baseline, 56 years [SD, 8 years]), 4607 CHD and 3253 stroke events were recorded (median follow-up, 8.1 years). The HR per 1-SD higher depression score for CHD was 1.11 (95% CI, 1.08-1.14); stroke, 1.10 (95% CI, 1.06-1.14); and CVD, 1.10 (95% CI, 1.08-1.13). The corresponding incidence rates per 10 000 person-years of follow-up among individuals with PHQ-2 scores of 4 or higher vs 0 were 20.9 vs 14.2 for CHD events, 15.3 vs 10.2 for stroke events, and 36.2 vs 24.5 for CVD events. The magnitude and statistical significance of the HRs were not materially changed after adjustment for additional risk factors. Conclusions and Relevance: In a pooled analysis of 563 255 participants in 22 cohorts, baseline depressive symptoms were associated with CVD incidence, including at symptom levels lower than the threshold indicative of a depressive disorder. However, the magnitude of associations was modest.

Cognitive Function and Impairment in Older, Rural South African Adults: Evidence from "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in Rural South Africa".

BACKGROUND/AIMS: We aimed to estimate the prevalence of cognitive impairment, and the sociodemographic and comorbid predictors of cognitive function among older, rural South African adults. METHODS: Data were from a population-based study of 5,059 adults aged ≥40 years in rural South Africa in 2015. Cognitive impairment was defined as scoring ≤1.5 SDs below the mean composite time orientation and memory score, or requiring a proxy interview with "fair" or "poor" proxy-reported memory. Multiple linear regression estimated the sociodemographic and comorbid predictors of cognitive score, with multiplicative statistical interactions between each of age and sex with education. RESULTS: Cognitive impairment increased with age, from 2% of those aged 40-44 (11/516) to 24% of those aged ≥75 years (214/899). The independent predictors of lower cognitive score were being older, female, unmarried, not working, having low education, low household wealth, and a history of cardiovascular conditions. Education modified the negative associations between female sex, older age, and cognitive function score. CONCLUSIONS: The prevalence of cognitive impairment increased with age and is comparable to rates of dementia reported in other sub-Saharan African countries. Age and sex differences in cognitive function scores were minimized as education increased, potentially reflecting the power of even poor-quality education to improve cognitive reserve.

Effects of the Affordable Care Act Medicaid Expansion on Subjective Well-Being in the US Adult Population, 2010-2016.

Objectives. To determine whether the 2014 Affordable Care Act Medicaid expansion affected well-being in the low-income and general adult US populations.Methods. We obtained data from adults aged 18 to 64 years in the nationally representative Gallup-Sharecare Well-Being Index from 2010 to 2016 (n = 1 674 953). We used a difference-in-differences analysis to compare access to and difficulty affording health care and subjective well-being outcomes (happiness, sadness, worry, stress, and life satisfaction) before and after Medicaid expansion in states that did and did not expand Medicaid.Results. Access to health care increased, and difficulty affording health care declined following the Medicaid expansion. Medicaid expansion was not associated with changes to emotional states or life satisfaction over the study period in either the low-income population who newly gained health insurance or in the general adult population as a spillover effect of the policy change.Conclusions. Although the public health benefits of the Medicaid expansion are increasingly apparent, improved population well-being does not appear to be among them.Public Health Implications. Subjective well-being indicators may not be informative enough to evaluate the public health impact of expanded health insurance.

Does optimal parenting style help offspring maintain healthy weight into mid-life?

An authoritative parenting style is generally associated with healthier body weight in children and adolescents. However, whether the protective effect of an authoritative style on offspring body weight may persist into adulthood has seldom been investigated. In this study we examined the longitudinal association between parenting style and body mass index (BMI) change in mid-life. Longitudinal data from the Midlife in the United States Study (N = 3929) were analyzed using generalized estimating equations, adjusting for a range of relevant covariates. Parenting styles were assessed at phase I (1995-1996) using items measuring parental warmth and control, while BMI was assessed at phases I and II (2004-2006). Four parenting styles were derived following prior research: authoritative, authoritarian, permissive, and uninvolved styles. Compared to an authoritative style, an authoritarian style was associated with 14% higher increase in the standardized BMI change score (ß = 0.14, 95% confidence interval: 0.03, 0.26). While there was suggestive evidence that an uninvolved versus authoritative style might also be associated with greater BMI increase, we found no differences between a permissive and authoritative style. This study suggested that the protective effect of an authoritative parenting style on offspring body weight may persist well into mid-life, particularly as compared to the authoritarian style and possibly the uninvolved style. Such work may reinforce the importance of a public health focus on improving parenting practices and suggest the value of implementing parenting programs, as one strategy for increasing the likelihood that individuals can maintain healthy weight well into adulthood.

Education modifies the relationship between height and cognitive function in a cross-sectional population-based study of older adults in Rural South Africa.

We aimed to estimate the relationship between height (a measure of early-life cumulative net nutrition) and later-life cognitive function among older rural South African adults, and whether education modified this relationship. Data were from baseline in-person interviews with 5059 adults ≥ 40 years in the population-based "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI) study in Agincourt sub-district, South Africa, in 2015. Linear regression was used to estimate the relationship between height quintile and latent cognitive function z-score (representing episodic memory, time orientation, and numeracy), with adjustment for life course covariates and a height-by-education interaction. Mean (SD) height was 162.7 (8.9) cm. Nearly half the sample had no formal education (46%; 2307/5059). Mean age- and sex-adjusted cognitive z-scores increased from - 0.68 (95% CI: - 0.76 to - 0.61) in those with no education in the shortest height quintile to 0.62 (95% CI: 0.52-0.71) in those with at least 8 years of education in the tallest height quintile. There was a linear height disparity in cognitive z-scores for those with no formal education (adjusted ß = 0.10; 95% CI: 0.08-0.13 per height quintile), but no height disparity in cognitive z-scores in those with any level of education. Short stature is associated with poor cognitive function and may be a risk factor for cognitive impairment among older adults living in rural South Africa. The height disparity in cognitive function was negated for older adults who had any level of education.

Cognitive function and cardiometabolic disease risk factors in rural South Africa: baseline evidence from the HAALSI study.

BACKGROUND: Evidence on cognitive function in older South Africans is limited, with few population-based studies. We aimed to estimate baseline associations between cognitive function and cardiometabolic disease risk factors in rural South Africa. METHODS: We use baseline data from "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI), a population-based study of adults aged 40 and above in rural South Africa in 2015. Cognitive function was measured using measures of time orientation, immediate and delayed recall, and numeracy adapted from the Health and Retirement Study cognitive battery (overall total cognitive score range 0-26). We used multiple linear regression to estimate associations between cardiometabolic risk factors (including BMI, hypertension, dyslipidemia, diabetes, history of stroke, alcohol frequency, and smoking status) and the overall cognitive function score, adjusted for potential confounders. RESULTS: In multivariable-adjusted analyses (n = 3018; male = 1520; female = 1498; median age 59 (interquartile range 50-67)), cardiometabolic risk factors associated with lower cognitive function scores included: diabetes (b = - 1.11 [95% confidence interval: - 2.01, - 0.20] for controlled diabetes vs. no diabetes); underweight BMI (b = - 0.87 [CI: - 1.48, - 0.26] vs. normal BMI); and current and past smoking history compared to never smokers. Factors associated with higher cognitive function scores included: obese BMI (b = 0.74 [CI: 0.39, 1.10] vs. normal BMI); and controlled hypertension (b = 0.53 [CI: 0.11, 0.96] vs. normotensive). CONCLUSIONS: We provide an important baseline from rural South Africa on the associations between cardiometabolic disease risk factors and cognitive function in an older, rural South African population using standardized clinical measurements and cut-offs and widely used cognitive assessments. Future studies are needed to clarify temporal associations as well as patterns between the onset and duration of cardiometabolic conditions and cognitive function. As the South African population ages, effective management of cardiometabolic risk factors may be key to lasting cognitive health.

Speed of Heart Rate Recovery in Response to Orthostatic Challenge.

RATIONALE: Speed of heart rate recovery (HRR) may serve as an important biomarker of aging and mortality. OBJECTIVE: To examine whether the speed of HRR after an orthostatic maneuver (ie, active stand from supine position) predicts mortality. METHODS AND RESULTS: A longitudinal cohort study involving a nationally representative sample of community-dwelling older individuals aged ≥50 years. A total of 4475 participants completed an active stand at baseline as part of a detailed clinic-based cardiovascular assessment. Beat-to-beat heart rate and blood pressure responses to standing were measured during a 2-minute window using a finometer and binned in 10-s intervals. We modeled HRR to the stand by age group, cardiovascular disease burden, and mortality status using a random effects model. Mortality status during a mean follow-up duration of 4.3 years served as the primary end point (n=138). Speed of HRR in the immediate 20 s after standing was a strong predictor of mortality. A 1-bpm slower HRR between 10 and 20 s after standing increased the hazard of mortality by 6% controlling for established risk factors. A clear dose-response relationship was evident. Sixty-nine participants in the slowest HRR quartile died during the observation period compared with 14 participants in the fastest HRR quartile. Participants in the slowest recovery quartile were 2.3× more likely to die compared with those in the fastest recovery quartile. CONCLUSIONS: Speed of orthostatic HRR predicts mortality and may aid clinical decision making. Attenuated orthostatic HRR may reflect dysregulation of the parasympathetic branch of the autonomic nervous system.

Bidirectional, Temporal Associations of Sleep with Positive Events, Affect, and Stressors in Daily Life Across a Week.

BACKGROUND: Sleep is intricately tied to emotional well-being, yet little is known about the reciprocal links between sleep and psychosocial experiences in the context of daily life. PURPOSE: The aim of this study is to evaluate daily psychosocial experiences (positive and negative affect, positive events, and stressors) as predictors of same-night sleep quality and duration, in addition to the reversed associations of nightly sleep predicting next-day experiences. METHODS: Daily experiences and self-reported sleep were assessed via telephone interviews for eight consecutive evenings in two replicate samples of US employees (131 higher-income professionals and 181 lower-income hourly workers). Multilevel models evaluated within-person associations of daily experiences with sleep quality and duration. Analyses controlled for demographics, insomnia symptoms, the previous day's experiences and sleep measures, and additional day-level covariates. RESULTS: Daily positive experiences were associated with improved as well as disrupted subsequent sleep. Specifically, positive events at home predicted better sleep quality in both samples, whereas greater positive affect was associated with shorter sleep duration among the higher-income professionals. Negative affect and stressors were unrelated to subsequent sleep. Results for the reversed direction revealed that better sleep quality (and, to a lesser degree, longer sleep duration) predicted emotional well-being and lower odds of encountering stressors on the following day. CONCLUSIONS: Given the reciprocal relationships between sleep and daily experiences, efforts to improve well-being in daily life should reflect the importance of sleep.

Prevalence and correlates of frailty in an older rural African population: findings from the HAALSI cohort study.

BACKGROUND: Frailty is a key predictor of death and dependency, yet little is known about frailty in sub-Saharan Africa despite rapid population ageing. We describe the prevalence and correlates of phenotypic frailty using data from the Health and Aging in Africa: Longitudinal Studies of an INDEPTH Community cohort. METHODS: We analysed data from rural South Africans aged 40 and over. We used low grip strength, slow gait speed, low body mass index, and combinations of self-reported exhaustion, decline in health, low physical activity and high self-reported sedentariness to derive nine variants of a phenotypic frailty score. Each frailty category was compared with self-reported health, subjective wellbeing, impairment in activities of daily living and the presence of multimorbidity. Cox regression analyses were used to compare subsequent all-cause mortality for non-frail (score 0), pre-frail (score 1-2) and frail participants (score 3+). RESULTS: Five thousand fifty nine individuals (mean age 61.7 years, 2714 female) were included in the analyses. The nine frailty score variants yielded a range of frailty prevalences (5.4% to 13.2%). For all variants, rates were higher in women than in men, and rose steeply with age. Frailty was associated with worse subjective wellbeing, and worse self-reported health. Both prefrailty and frailty were associated with a higher risk of death during a mean 17 month follow up for all score variants (hazard ratios 1.29 to 2.41 for pre-frail vs non-frail; hazard ratios 2.65 to 8.91 for frail vs non-frail). CONCLUSIONS: Phenotypic frailty could be measured in this older South African population, and was associated with worse health, wellbeing and earlier death.

Strengthening capacity to research the social determinants of health in low- and middle-income countries: lessons from the INTREC programme.

BACKGROUND: The INDEPTH Training & Research Centres of Excellence (INTREC) collaboration developed a training programme to strengthen social determinants of health (SDH) research in low- and middle-income countries (LMICs). It was piloted among health- and demographic researchers from 9 countries in Africa and Asia. The programme followed a blended learning approach and was split into three consecutive teaching blocks over a 12-month period: 1) an online course of 7 video lectures and assignments on the theory of SDH research; 2) a 2-week qualitative and quantitative methods workshop; and 3) a 1-week data analysis workshop. This report aims to summarise the student evaluations of the pilot and to suggest key lessons for future approaches to strengthen SDH research capacity in LMICs. METHODS: Semi-structured interviews and questionnaires with 24 students from 9 countries in Africa and Asia were used to evaluate each teaching block. Information was collected about the students' motivation and interest in studying SDH, any challenges they faced during the consecutive teaching blocks, and suggestions they had for future courses on SDH. RESULTS: Of the 24 students who began the programme, 13 (54%) completed all training activities. The students recognised the need for such a course and its potential to improve their skills as health researchers. The main challenges with the online course were time management, prior knowledge and skills required to participate in the course, and the need to get feedback from teaching staff throughout the learning process. All students found the face-to-face workshops to be of high quality and value for their work, because they offered an opportunity to clarify SDH concepts taught during the online course and to gain practical research skills. After the final teaching block, students felt they had improved their data analysis skills and were better able to develop research proposals, scientific manuscripts, and policy briefs. CONCLUSIONS: The INTREC programme has trained a promising cadre of health researchers who live and work in LMICs, which is an essential component of efforts to identify and reduce national and local level health inequities. Time management and technological issues were the greatest challenges, which can inform future attempts to strengthen research capacity on SDH.